In a typical electrostatographic printing machine (such as a photocopier, laser printer, facsimile machine or the like), an imaging member is employed and is exposed to an image to be printed. Exposure of the imaging member to the image to be printed records an electrostatic latent image on the imaging member corresponding to the informational areas contained within the image to be printed. Generally, the electrostatic latent image is developed by bringing a toner or developer mixture into contact therewith.
One type of developer used in such printing machines is a liquid developer comprising a liquid carrier having toner particles dispersed therein. Generally, the toner is made up of resin and a suitable colorant such as a dye or pigment. Conventional charge director compounds may also be present. The liquid developer material is brought into contact with the electrostatic latent image and the colored toner particles are deposited thereon in image configuration.
The developed toner image recorded on the imaging member is transferred to an image receiving substrate such as paper via an intermediate transfer member. The toner particles may be transferred by heat and/or pressure to an intermediate transfer member, or more commonly, the toner image particles may be electrostatically transferred to the intermediate transfer member by means of an electrical potential between the imaging member and the intermediate transfer member. After the toner has been transferred to the intermediate transfer member, it is then transferred to the image receiving substrate, for example by contacting the substrate with the toner image on the intermediate transfer member under heat and/or pressure.
Intermediate transfer members enable high throughput at modest process speeds. In four-color photocopier systems, the intermediate transfer member also improves registration of the final color toner image. In such systems, the four component colors of cyan, yellow, magenta and black may be synchronously developed onto one or more imaging members and transferred in registration onto an intermediate member at a transfer station.
In electrostatographic printing machines in which the toner image is transferred from the intermediate transfer member to the image receiving substrate, it is important that the transfer of the toner particles from the intermediate transfer member to the image receiving substrate be as close as possible to 100%. Less than complete transfer to the image receiving substrate results in image degradation and low resolution. Completely efficient transfer is particularly important when the imaging process involves generating full color images since undesirable color deterioration in the final colors can occur when the color images are not completely transferred from the intermediate transfer member.
Thus, it is important that the intermediate transfer member surface has excellent release characteristics with respect to the toner particles. Conventional materials known in the art for use as intermediate transfer members often possess the strength, conformability and electrical conductivity necessary for use as intermediate transfer members, but can suffer from poor toner release characteristics, especially with respect to higher gloss image receiving substrates.
A need remains for an intermediate transfer member that exhibits substantially 100% toner transfer, without system failure, to image receiving substrates having glosses ranging from low to very high. Further, a need remains for a method for producing high resolution images upon image receiving substrates having various glosses from such an intermediate transfer member.